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500 BCE
Alchemists
Developed the theory that all metals are composed of mercury and sulfur and that it is possible to change base metals into gold. -
442 BCE
Democritus
Greek philosopher, who developed the atomic theory of the universe,His atomic theory anticipated the modern principles of the conservation of energy and the irreducibility of matter. -
427 BCE
Plato
Plato was a Greek philosopher who is known best as a disciple of Socrates and carries on his work on the atomic theory. Plato introduced the atomic theory in which ideal geometric forms serve as atoms, according to which atoms broke down mathematically into triangles, such that the form elements had the following shape: fire (tetrahedron), air (octahedron), water (icosahedron), earth (cube). However, this was not the atomic theory fully, but rather the four element theory. -
384 BCE
Aristotle
Aristotle provided us with knowledge of natural science including Physics, which gives a vast amount of information on astronomy, meteorology, plants, and animals. -
Robert Boyle
Robert Boyle (1627-1691) is known as “The Father of Chemistry” for his discovery that atoms must exist based on the relationship between pressure and volume of gas. His theorem called Boyle’s Law reasons that because a fixed mass of gas can be compressed, gas must be made of particles, or atoms, because there is space between them. -
Lavoisier
French chemist, who is considered the founder of modern chemistry. Lavoisier clarified the concept of an element as a simple substance that could not be broken down by any known method of chemical analysis, and he devised a theory of the formation of chemical compounds from elements. -
John Dalton
British chemist and physicist, who developed the atomic theory upon which modern physical science is founded.Dalton's most important contribution to science was his theory that matter is composed of atoms of differing weights and combine in simple ratios by weight. -
J.J. Thomson
J.J. Thomson discovered electrons and noticed that an atom can be divided. Also, he concluded atoms are made of positive cores and negatively charged particles within it. He developed the Plum Pudding Model before the atomic nucleus was discovered. -
Robert Millikan
determined the unit charge of the electron in 1909 with his oil drop experiment at the University of Chicago. Thus allowing for the calculation of the mass of the electron and the positively charged atoms. -
Neils Bohr
Bohr made numerous contributions to our understanding of atomic structure and quantum mechanics -
Henry G.J. Mosely
English physicist who experimentally demonstrated that the major properties of an element are determined by the atomic number, not by the atomic weight, and firmly established the relationship between atomic number and the charge of the atomic nucleus. -
The Curies
Pierre Curie and his wife Marie Curie stated that radioactive materials cause atoms to break down spontaneously, releasing radiation in the form of energy and subatomic particles. -
Solid Sphere of "Billiard Ball" Model
The Solid Sphere was created by John Dalton in the early 19th century. -
"Plum Pudding" Model
The Plum Pudding Model was invented by J.J Thompson. The plum pudding model is one of several historical scientific models of the atom. -
Albert Eintsein
Einstein was known as the creator of the special and general theories of relativity and for his intelligent hypothesis concerning the particle nature of light. -
Dmitri Mendeleev
Dmitri Ivanovich Mendeleev was a Russian chemist and inventor. He is best remembered for formulating the Periodic Law and creating a farsighted version of the periodic table of elements. -
Ernest Rutherford
physicist, who became a Nobel laureate for his pioneering work in nuclear physics and for his theory of the structure of the atom. -
Solar System Model
Solar System Model was invented by Neils Bohr. Solar System models, especially mechanical models, called orreries, that illustrate the relative positions and motions of the planets and moons in the Solar System have been built for centuries. While they often showed relative sizes, these models were usually not built to scale. -
Werner Cloud Model
Werner Heisenberg, a German physicist and philosopher who discovered (1925) a way to formulate quantum mechanics in terms of matrices. For that discovery, he was awarded the Nobel Prize for Physics for 1932. In 1927 he published his uncertainty principle, upon which he built his philosophy and for which he is best known. He also made important contributions to the theories of the hydrodynamics of turbulent flows, the atomic nucleus, ferromagnetism, cosmic rays, and subatomic -
Electron Cloud Model
The Electron Cloud Model was created by Erwin Schrodinger and werner Heisenberg. The model is a way to help visualize the most probable position of electrons in an atom.
